Generally, a compressor used for air conditioning systems receives, from an evaporator, refrigerant that has passed through an evaporating process, converts the refrigerant into a high-temperature and high-pressure phase in which it can be easily liquefied, and then transfers it to a condenser. As such, the compressor is operated to compress refrigerant that is transferred via the evaporator.
Compressors are classified into a reciprocating compressor in which a drive unit for compressing refrigerant reciprocates to perform the compression operation, and a rotary compressor in which a drive unit rotates to perform the compression operation. Reciprocating compressors are classified into a crank type in which drive force of the drive unit is transmitted to a plurality of pistons through a crank, a swash plate type in which the drive force is transmitted to a rotating shaft provided with a swash plate, and a wobble plate type in which a wobble plate is used.
In such compressors, refrigerant and oil are mixed with each other during use, and the mixture is separated into pure gas phase refrigerant and oil by an oil separator. The refrigerant is moved to an evaporator, and the oil is reused for lubrication in a compressor.
At an initial stage of the operation of the compressor, a small amount of metal foreign substances may be generated by friction between components of the compressor. If foreign substances are applied to components of the compressor in which friction is generated, unnecessary abrasion or noise may be caused. Consequently, a technique capable of separating foreign substances from oil has been required.